One police officer was killed and seven others were injured in a blast on Friday evening in Grozny, capital of Russia's turbulent southern republic of Chechnya, RIA Novosti news agency reported.

Militants attacked a police van outside a market with a grenade launcher before the explosion, but the vehicle was empty, a spokesman for local investigators said.

A landmine went off after policemen arrived at the scene, leaving one dead and another seven injured, the spokesman said.

According to preliminary information, no civilians were injured in the incident.

The North Caucasus republic of Chechnya, along with neighboring Dagestan and Ingushetia, has seen an upsurge of militant violence in recent months, with attacks on police and officials being reported almost daily.